Chimney construction



March l, 1960 R. J. sl'MPsoN 2,926,517

CHIMNEY CONSTRUCTION Filed Dec. l0, 1956 d A j .4 W 34 y INVENTOR. osfeJ. unpsolv .ttamgs This invention relatesto chimneys' and has particular ted rates .Patent O i'eference'to a smoke chamber construction which finds particular utility in connection with the chimneys of fireplaces such as are used for residential cheating.

"In the construction of chimneys, and particularly in the" construction of those chimneys used for residential fireplaces,l it is common practice to 4provide a smoke chamber Ybetween the fire box and the flue which interconnects the fireplace throatwiththe flue proper. Such smokechambers are of tapered cross-section, forming a transition between the relatively large cross-section of .the vchimney just above the fireplace throat to the much smaller cross-section of the flue. When, as is often the case, such 'chimneys are constructed of discrete elements or building blocks such as bricks `or stones, the building blocks 'must be so placed and laid as top'rovide therequired inward and upward taper o-f the sides of the smoke chamber. This must be done in suchra manner as `to provide an adequate support for the flue lining which is rested on the Vupper edge of the -walls of the smoke chamber. lThis construction is ordinarily effected by corbelling, an exacting and time-consuming operation requiring -great skill and extreme care, as `a consequence of `whichthe construction of 'smoke chambers represents a relatively lcostly item inthe construction of the fireplace and associated chimney.

In order that the fireplace and chimney may operate properly, the inner surfaces of the smoke chamber must be smooth and free of the lprojections and discontinuities characteristic of ycorbels "inf-order to reduce-"to 'a minimum the frictional resistance to the passage of the fsmoke and flue gases. Consequently, it isva common practice to apply mortar ora similar `plaster tothe inner surfaces to provide the desired smooth andcontinuous surface. This practiceentails certain disadvantages since, unless carefully and expertly done, the plaster mayV in time be loosened by the expansion and contraction ofthe structure which results from the wide variations in operating temperature,

".It is, therefore, an object of this invention to provide a chimney construction which overcomes the abovementioned disadvantages by providing for simple andrapid construction of a smoke chamber and which does not require highly skilled labor for its erection.

v It is another object of this invention to provide a method of constructing smoke chambers in block chimneys which consists in placing a pre-formed support at the smoke chamber location and setting the blocks against said support, whereby the same are vproperly positioned and supported during the placing and setting thereof.

It is also an object of this invention to provide a method of the character set forth in the preceding paragraph in which said support ,is perforated and mortar is used to secure said blocks to each other and to said support, and wherein mortar extruded through the perforations is troweled .to a smooth-finish to provide an linner plastered layer',` `whereby said support serves also to reinforce said mortar and to secure said plasterlayer against loosening'and falling.

It is an additional object of this invention to provide a pre-formed support for'the walls of smoke chambers in chimney constructions comprising upper and lower frame members having dimensions conforming to the top and bottom cross-sections of the smoke chamber, said frames being spaced vertically by supporting members secured to and 'interconnecting said frames, and a sheet of perforated "material surrounding said frames and extending ltherebetween.

`It is an additional object of this invention to provide a Vpre-formed support of the character described in the preceding paragraph in which said frames an'd supporting members Vare formed of metal rods or bars and in which said perforated material'comprises a metal screen, such as metal lath.

It is a still further 'object of this invention "to provide a smokerchamber for chimneys comprising a rigid supporting and reinforcing structure including a tapered, a tubular or open-endedbox having metal mesh walls" secured to a metal framework, said box being open at the top and bottom, a `plastered layer on the inner surface of said walls formed of mortar keyed through the openings in =said metal mesh, 'and an outer layer vof building blocks such as lbricks orstones set against said walls and secured thereto and `to leach other by said mortar.

lOther objects and advantages 'of this invention will be apparent from .aV consideration of the following speci fireplace showing the lire box opening and indicating by dotted lines the 'smoke vchamber and flue; Y

Figure 2 `is an :enlarged fragmentary sectional view taken substantiallyalong `the lines2-2 of Figuresl 1 and 3 and `illustrating the construction of the upper -part of the fire box, the smoke chamber, and the lower part of the ue; n

Figure 3 is an enlarged fragmentary sectional view similar to Figure A2 but ltaken at right angles 4thereto as indicated by the lines 3--3 of .Figure 2; and

Figure V4 'is a perspective view 'illustrating a preferred form ofconstruction of a pre-formed support used in the practice of the method of this invention and "inrcorp'or'at'f-:d as` apart of the smoke chamber construction.` i' i 'Referring to the drawings wherein a preferred embodiment` of rthe invention is shown, Figure ,l illustrates a residential fireplace of the flush type, the fireplace comprising-a fireplace front indicatedgenerally 1 at 10 formed of discrete building blocks such as bricks, as vshown in Figure 1. The structurel() defines a fireplace opening 11 communicating with 4a fire box 12.- The chimney proper indicated by 'the dotted'lines 13 is set back behind the y'building wall which "isrepresented Vat 9.

Asis best shown in Figures `2 and 3, the structure I0 is formed of brick laid'in the conventional manner. The chimney 13 is defined by'ia rear wall 14 and a front wall 15, the latter being set back' as indicated at 16 to provide a suitable support for the building wall studs 17and plaster facing 18. The sides of the chimney are defined by inner walls I9'and outer walls 20. The inner walls 19 together with the front and 'rear walls 14 and `15 define the iiue proper, the tiue being lined with an appro'- priate flue liner 21 which Tis supported and resteduponi 'a shelf'or projection '22 formed by courses of bricks-23 Y surrnounting the smoke chamber indicated generallyfat kas is represented at 29. l.

The present invention is concerned with the construc- .tion of the smoke Vchamber'24'. It will be appreciated `that the construction of thatpart of theV chimney lying vabove'the flue liner support 22, 23 proceeds relatively rapidly and the bricks forming the same may be laid by relatively unskilled masons. However,-as YmayV be seen fromFigure 3, the smoke chamber 24 requires the construction of atleast two Vcorbels formed by inwardly staggered courses of brick such as are shown at 30 in Figure 3. The "construction of a corbel requires a high degree of masonry skill and is work which must necessarily proceed slowly. if a good, sound, strong structure Vis to result.

According to the present invention, the construction is built up to the bottom of the smoke chamber, that is to the brick courses indicated by reference character 31 in Figures 2 and 3, in the conventional fashion. At this point a novel smoke chamber preformed support 32 is used lto greatly facilitate the construction by providing a support for the corbelled courses 30 and at the same time adequately support and hold an inner plastered layer 33 which provides the desired smooth and unbroken interior surface. The construction of the smoke chamber support is illustrated in detail in Figure `4.

As may be seen in Figure 4, the smoke chamber support 32 comprises an upper frame 34 and a lower frame 35' held in spaced parallel' relation by interconnecting supporting members 36 extended from the corners'of the lower frame 35 to corresponding corners of the upper frame.,34. The frames 34 and 35 are-shaped to conform to the cross-sectional shape of the flue lining 21 and the lower portion of the smoke chamber, as defined by the brick courses 31. These frames are preferably constructed of iron rods suitably bent and welded, but may be made of angle iron or other structural members, similar material preferably being used for the; interconnecting supports 36, the latter being appropriately secured to the corners of the frames as shown as by welding or similar means. n

The box-like support 32 is of course open at 'the top and bottom; the sides, however, are covered with a metal mesh or perforated material such as metal lath,- as indicated at 37, the material covering the four sides of the box-like form and being appropriately secured to the previously-described structure, as by spot-welding, wire ties, or other equivalent means.

In utilizing the support 32 the same is rested on the upper surface of the brick course 31 as shown in Figures 2 and 3 and the perforated walls 37 are generously coated with mortar. The individual courses 30 forming the corbel are then laid by merely placing them in contact with the walls 37 of the support 32, mortar being suitably applied to the bricks to bond the same to each other as in conventional brick-laying practice. Since it is a very simple operation merely to slide each of the bricks of the courses 30 inwardly into contact with the perforated walls 37, the corbel is formed very rapidly and in such a way as not to require the exercise of any great degree of skill. The mortar which is applied to the bricks in the usual fashion adheres, of course, to the mortar coating previously 'applied to the perforated walls 37 so as to provide an integral bond between adjacent bricks and between those bricks and the smoke chamber wall-supporting member. The operation of sliding the bricks inwardly into contact with the lperforated walls 37 forces 4 a substantial amount of the mortar through the perforations to key the mortar to the structure. This inwardly protruding mortar is then troweled to a smooth finish to provide the inner plaster coating'33.

It will be seen that the lower frame member 35 is rested upon the upper surface of the brick course 31 and that the upper brick course 23 is correspondingly rested upon the upper frame member 34. The corbel formed by the courses 30 serve to provide the necessary structure for supporting the upper course 23 from the structure which lies below the course 31. From the upper end of the smoke chamber 24, as defined by the course 23, the flue construction proceeds in the conventional fashion.

It will be seen that when the structure is completed, there is provided a smoke chamber which is characterized by a rigid supporting and reinforcing structure carrying on its inner surface a plastered layer formed of mortarfkeyed through the openings in the metal mesh, and an outer layer formed of bricks'or other building blocks which are .set `against the walls of the support and secured thereto and to each other by the mortar used in the construction. ,The support thus not only provides for ready and rapid construction of the smokechamber by relatively unskilled masons, butalso provides' for a structural reinforcement of the nished structure. What is even more important, the inner plastered layer is mechanically secured to the rest of the structure by reason of the keys which are formed through the openings in the metal lath, thus avoiding all possibility of the plastered layer 33 coming loose and falling as sometimes happens because of the extreme changes in temperature to which the structure is subjected during normal operation.

While the preferred embodiment of the invention has been illustrated and described herein, the invention is not to be limited to the details shown and described, except as defined in the appended claim.

l claim:

A chimney smoke chamber comprising: a rigid framework comprising spaced parallel upper and lower generally rectangular frame members having dimensions corresponding respectively to the top and bottom crosssections of the smoke chamber and having a plurality of supporting members each extending inwardly and up wardly from said lower frame member to said upper frame member at the corners thereof and rigidly secured to said frame members, said frame members and said supporting members. comprising metal rods; a side wall secured to said framework extending inwardly and upwardly from said lower frame member to said upper frame member, said side wall comprising a substantially continuous pieceof an expanded metal lath material; an outer layer of building blocks set against and completely surrounding said side wall; and mortar interlocking said building blocks to one another and to said wall, said mortar being keyed through the openings in said metal lath material and being smoothly troweled on theV interior surface of said wall to completely conceal said wall and framework.

References Cited in the le of this patent i y UNITED STATES PATENTS i Y 1897 Y' 496,778, Beigium A of- 

